DIY_EFI Digest Saturday, October 9 1999 Volume 04 : Number 570 In this issue: RE: How completcated does Efi HAVE to be? Not that complicated! Re: DIY_EFI Digest V4 #569 Re: Up Up and away Lungs Online American engine sizes American engine sizes See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 9 Oct 1999 11:02:32 +0100 From: "Rich M" Subject: RE: How completcated does Efi HAVE to be? Not that complicated! DIY_EFI Digest Friday, October 8 1999 Volume 04 : Number 568 Date: Fri, 08 Oct 1999 09:40:33 -0700 From: Will McGonegal Subject: RE: How completcated does Efi HAVE to be? Not that complicated! >>>to do a reasonable job of EFI. However, you WILL need the crankshaft position >>>sensor, which means you need the flywheel, transfer case and the actual >>>sensor. >>Surely it doesn't have to be *that* accurate? Why not use the coil? 2 per >>Rev should be enough, you only need speed not accurate position? >>Ade >I'd agree, you DON'T need the crankshaft position sensor (flywheel, transfer case and >the actual sensor). An input from the spark ignition will sufice (distributor? >surely that's already on the engine). Bosch LE/LE2 based systems have been taking EFi trigger signals from the ignition for years.. Don't lose sight of the big problem with mini's - siamesed ports! For those not so familiar, the head has two inlet ports which each split in two to feed two inlet valves; Cyls 1&2 are fed by one inlet tract and cyls 3&4 fed from the second. Throw the firing order into the equation, and you will appreciate the problem of mixture distribution, specially from a throttle body injection arrangement. for this reason, Mini's run with uneven mixture across the cylinders even with carbs that feed fuel into the airstream continuously. Consider what happens when you inject pulses of fuel into the airflow way back at the throttle body, synchronous with the engine cycle. This is why I believe some (if not all) TBi sytems inject 'asynchronously' (randomly?). Certainly Vauxhall/Opel Multec TBI systems inject 5 pulses per cycle to try and spread out the uneven distribution so that each cylinder gets a fighting chance of seeing reasonable mixture on average. Multipoint systems with an injector per cylinder obviously overcome most of these problems, but on the mini's siamesed ports it's difficult to physically arrange this as the port split is in the head. Don't let this put you off - Rover obviously achieve reasonable results; indeed if you 're not using the 'A' series engine, and you've got an 8-port head, then please bung this message in the bin... Good luck! Rich ------------------------------ Date: 10 Oct 99 00:17:15 +1200 From: "Tom Parker" Subject: Re: DIY_EFI Digest V4 #569 DIY_EFI Digest wrote: sorry for mangling the quotes... >> No, it does. You have to have a very good accuracy (I think the minimum >> is 6 "steps" per revolution) because otherwise the system will get >> confused when the engine changes speed quickly. >I did some calculations to check into what kind of errors you'd get on your >speed under constant acceleration if you used a single pulse per revolution >Speed [rpm]=> V1 = 60.0 / (T1 - T0) >More pulses per revolution will increase accuracy but do all applications >need it? I think you could do it with a pulse every second revolution and >have it run better then a carburetor. >Will McGonegal If you hook up to the coil, using a distributor to drive the ignition, then you get 2 pulses per revolution on 4 cyclinders, 3 from 6 cycl and 4 from 8 I think you could easily do with only the distributor as a crank position input, SO LONG AS YOU DO NOT CONTROL THE IGNITION SYSTEM from the computer. If you want to do ignition timing, then those errors are going to hit you (well, I have a qualitative feeling that they will matter). - -- Tom Parker - parkert@xxx.nz - http://www.geocities.com/MotorCity/Track/8381/ ------------------------------ Date: Fri, 08 Oct 1999 21:00:20 +0100 From: Ade + Lamb Chop Subject: Re: Up Up and away At 05:00 08/10/99 -0400, you wrote: >Now I am not saying that a Pulsewidth[MAP,RPM] table will not produce a nice >clean precise fuel mixture for an engine. It does. But, the MAP and the RPM >only tell you how fast the air in the intake manifold will travel into the >cylinder and not how fast the replacement air moves that is drawn into the >manifold past the throttle plate. Yes, on average a higher altitude will >create an average lower MAP and lean off the mixture a little; but not enough >simply because the Dyno runs for that MAP and RPM value had a different pressure >outside the throttle plate and the replacement air moves at a higher velocity. Right you have sold me, BUT (very big but) How bad is the effect? It cannot be that bad other wise cars with Carbs would suffer problems wouldn't they? Unless you are wrong :-) Ade ------------------------------ Date: Sat, 09 Oct 1999 06:42:39 -0700 From: garfield@xxx.com (Gar Willis) Subject: Lungs Online On Sat, 9 Oct 1999 05:00:01 -0400, DIY_EFI-Digest-Owner@xxx.edu (DIY_EFI Digest) wrote: >Well CSH, HQ is back on line. >Got one very good lung, (verified by X-Ray, by me). >Amazing capacacity. Major congrats, Bruce! And it sounds like you had a bit of an ordeal there, eh? Oh well, that sorta operation would stop anyone's heart. :) Good to have ya back, and kickin. Gar ------------------------------ Date: Sat, 09 Oct 1999 13:10:24 +0100 From: Ade + Lamb Chop Subject: American engine sizes At 05:00 09/10/99 -0400, DIY_EFI Digest wrote: >i would have to some how reprogram the GM unit as the toyota motor is only >2 litre. Sorry guys not much to do with Efi but... This make me giggle. Us people who are into minis say WOW... when sombody squeezes a 1600honda engine in a Mini The biggest engine you see in any 'average' car in this country is a 2 litre it is not until you start talking about top of the range BMWs and other BIG fast stuff that it gets much over near 3 litres!!! BTW a std mini engine is 1.3 litres and the first ones were 848cc!! Ade ------------------------------ Date: Sat, 09 Oct 1999 13:10:24 +0100 From: Ade + Lamb Chop Subject: American engine sizes At 05:00 09/10/99 -0400, DIY_EFI Digest wrote: >i would have to some how reprogram the GM unit as the toyota motor is only >2 litre. Sorry guys not much to do with Efi but... This make me giggle. Us people who are into minis say WOW... when sombody squeezes a 1600honda engine in a Mini The biggest engine you see in any 'average' car in this country is a 2 litre it is not until you start talking about top of the range BMWs and other BIG fast stuff that it gets much over near 3 litres!!! BTW a std mini engine is 1.3 litres and the first ones were 848cc!! Ade ------------------------------ End of DIY_EFI Digest V4 #570 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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